This invention relates to a method of recoiling metal material cut into individual strands by a slitter.
Metal procedures manufacture sheets of metal material in coiled form having a substantial width. Generally before such coiled metal can be utilized for fabrication purposes it must be cut by a slitter into strips or strands of desired width and recoiled for shipping and handling. Due to the manner in which the large coils of metal sheeting are produced, the cross sectional thickness of the sheets varies from a maximum in its center to a minimum at each of its opposite sides. Thus, when such a coiled sheet of metal is slit into strands, the thickness of some strands will exceed the thickness of the other strands. Heretofore strands of slit metal sheet material have been coiled by being attached to the drum of a recoiler and wound thereupon by rotation of the drum. Due to the varying thicknesses of the strands, those strands of greater thickness will be wound at greater linear speed then those strands of lesser thickness which causes the thinner strands to appreciably sag between the slitter and recoiler. To accommodate such sagging strands of metal material, a pit is commonly dug between the slitter and recoiler for receiving such strands. In addition to a pit for receiving the sagging strands of slit material, elaborate tensioning devices have been incorporated in prior art metal slitting lines for the purpose of maintaining separation between the strands and properly tensioning the strands prior to being wound upon the recoiler. Examples of such devices are disclosed in U.S. Pat. No. 3,883,088 and 3,672,595.
A similar problem regarding the lack of uniformity in linear winding speed for slit material has been encountered when slitting webs of plastic or similar non-metallic material and rewinding the slit material into thin rolls. U.S. Pat. No. 2,985,398 is an example of the elaborate rewinding systems devised to equalize the linear speed at which such slit material is rewound into rolls.
In the following described invention an economical and simplified method for rewinding slit metal material is disclosed in which existing slitting apparatus can be utilized without the need for a pit between the slitter and recoiler and elaborate tensioning devices.